TypeBox Schemas: Gateway Protocol Source of Truth

TypeBox serves as a schema library built around TypeScript. OpenClaw relies on it to define the Gateway WebSocket protocol, covering the handshake, request/response patterns, and server events. These schemas power runtime validation through AJV, JSON Schema export, and Swift codegen for the macOS application. A single source of truth drives all downstream generation.

For broader protocol context, refer to Gateway architecture.

Mental model (30 seconds)

Gateway WS messages come in three frame types:

• Request: { type: "req", id, method, params }
• Response: { type: "res", id, ok, payload | error }
• Event: { type: "event", event, payload, seq?, stateVersion? }

A connect request is mandatory as the initial frame. Subsequently, clients invoke methods like health, send, and chat.send, and subscribe to events such as presence, tick, and agent.

Here is a minimal connection flow:

Client                    Gateway
  |---- req:connect -------->|
  |<---- res:hello-ok --------|
  |<---- event:tick ----------|
  |---- req:health ---------->|
  |<---- res:health ----------|

A summary of typical methods and events:

The canonical discovery inventory, as advertised, resides in src/gateway/server-methods-list.ts (listGatewayMethods, GATEWAY_EVENTS).

Where the schemas live

• Source barrels: the authoritative domain-module list is held by packages/gateway-protocol/src/schema-modules.ts, whereas the public schema.ts wrapper additionally surfaces ProtocolSchemas.
• Generator registry: ordered protocol-schema-fragment-*.ts files associate stable names with the canonical TypeBox objects from their owning modules. protocol-schemas.ts merges these fragments in a predetermined sequence and rejects any duplicate keys.
• Runtime validators (AJV): packages/gateway-protocol/src/index.ts
• Advertised feature/discovery registry: src/gateway/server-methods-list.ts
• Server handshake and method dispatch: src/gateway/server-core-runtime.ts
• Node client: src/gateway/client.ts
• Generated JSON Schema: dist/protocol.schema.json (produced at build time, not checked in)
• Generated Swift models: apps/shared/OpenClawKit/Sources/OpenClawProtocol/GatewayModels.swift

Current pipeline

• pnpm protocol:gen writes JSON Schema (draft-07) to dist/protocol.schema.json.
• pnpm protocol:gen:swift generates the Swift gateway models.
• pnpm protocol:check:swift verifies the committed Swift models without rewriting them.
• pnpm protocol:gen:kotlin generates the Android protocol models and constants.
• pnpm protocol:check checks the registry structure, runs all three generators, and verifies the committed Swift and Kotlin output (the JSON Schema output is a gitignored build artifact).

When a gateway schema affects native clients, run pnpm protocol:gen:swift, review the generated diff, then run pnpm protocol:check:swift. Commit the schema and GatewayModels.swift update together. Stable decoding behavior belongs in the focused GatewayModelsCompatibilityTests.swift regressions rather than in handwritten model copies.

How the schemas are used at runtime

• Server side: every inbound frame is validated with AJV. The handshake only accepts a connect request whose params match ConnectParams.
• Client side: the JS client validates event and response frames before using them.
• Feature discovery: the Gateway sends a conservative features.methods and features.events list in hello-ok, from listGatewayMethods() and GATEWAY_EVENTS.
• That discovery list is not a generated dump of every callable helper in coreGatewayHandlers; some helper RPCs are implemented in src/gateway/server-methods/*.ts without being enumerated in the advertised feature list.

Example frames

Connect (first message):

{
  "type": "req",
  "id": "c1",
  "method": "connect",
  "params": {
    "minProtocol": 3,
    "maxProtocol": 4,
    "client": {
      "id": "openclaw-macos",
      "displayName": "macos",
      "version": "1.0.0",
      "platform": "macos 15.1",
      "mode": "ui",
      "instanceId": "A1B2"
    }
  }
}

Hello-ok response:

{
  "type": "res",
  "id": "c1",
  "ok": true,
  "payload": {
    "type": "hello-ok",
    "protocol": 4,
    "server": { "version": "dev", "connId": "ws-1" },
    "features": { "methods": ["health"], "events": ["tick"] },
    "snapshot": {
      "presence": [],
      "health": {},
      "stateVersion": { "presence": 0, "health": 0 },
      "uptimeMs": 0
    },
    "auth": { "role": "operator", "scopes": ["operator.read"] },
    "policy": { "maxPayload": 1048576, "maxBufferedBytes": 1048576, "tickIntervalMs": 30000 }
  }
}

Request and response:

{ "type": "req", "id": "r1", "method": "health" }

{ "type": "res", "id": "r1", "ok": true, "payload": { "ok": true } }

Event:

{ "type": "event", "event": "tick", "payload": { "ts": 1730000000 }, "seq": 12 }

Minimal client (Node.js)

Smallest useful flow: connect + health.

import { WebSocket } from "ws";

const ws = new WebSocket("ws://127.0.0.1:18789");

ws.on("open", () => {
  ws.send(
    JSON.stringify({
      type: "req",
      id: "c1",
      method: "connect",
      params: {
        minProtocol: 4,
        maxProtocol: 4,
        client: {
          id: "cli",
          displayName: "example",
          version: "dev",
          platform: "node",
          mode: "cli",
        },
      },
    }),
  );
});

ws.on("message", (data) => {
  const msg = JSON.parse(String(data));
  if (msg.type === "res" && msg.id === "c1" && msg.ok) {
    ws.send(JSON.stringify({ type: "req", id: "h1", method: "health" }));
  }
  if (msg.type === "res" && msg.id === "h1") {
    console.log("health:", msg.payload);
    ws.close();
  }
});

Worked example: add a method end-to-end

Example: add a new system.echo request that returns { ok: true, text }.

1. Schema (source of truth)

Add to packages/gateway-protocol/src/schema/system-info.ts (or the closest matching feature module):

export const SystemEchoParamsSchema = Type.Object(
  { text: NonEmptyString },
  { additionalProperties: false },
);

export const SystemEchoResultSchema = Type.Object(
  { ok: Type.Boolean(), text: NonEmptyString },
  { additionalProperties: false },
);

Add both entries to the closest semantic packages/gateway-protocol/src/schema/protocol-schema-fragment-*.ts file. Import the owner module as a namespace when that fragment does not already use it, then map the stable registry names to the canonical schema objects:

import * as system from "./system.js";

export const OperationsProtocolSchemas = {
  // Existing entries stay in their current order.
  // ...
  SystemEchoParams: system.SystemEchoParamsSchema,
  SystemEchoResult: system.SystemEchoResultSchema,
} as const;

Do not sort fragment keys or move existing entries: native code generation follows registry insertion order. protocol-schemas.ts owns the deliberate fragment order and should change only when introducing a new semantic fragment.

export type SystemEchoParams = Static<typeof SystemEchoParamsSchema>;
export type SystemEchoResult = Static<typeof SystemEchoResultSchema>;

2. Validation

In packages/gateway-protocol/src/index.ts, export an AJV validator:

export const validateSystemEchoParams = ajv.compile<SystemEchoParams>(SystemEchoParamsSchema);

3. Server behavior

Add a handler in src/gateway/server-methods/system.ts:

export const systemHandlers: GatewayRequestHandlers = {
  "system.echo": ({ params, respond }) => {
    const text = String(params.text ?? "");
    respond(true, { ok: true, text });
  },
};

Register it in src/gateway/server-methods.ts (already merges systemHandlers), then add "system.echo" to the listGatewayMethods input in src/gateway/server-methods-list.ts.

If the method is callable by operator or node clients, also classify it in src/gateway/method-scopes.ts so scope enforcement and hello-ok feature advertising stay aligned.

4. Regenerate

pnpm protocol:check

5. Tests and docs

Add a server test in src/gateway/server.*.test.ts and note the method in docs.

Swift codegen behavior

The Swift generator emits:

• a GatewayFrame enum with req, res, event, and unknown cases
• strongly typed payload structs/enums
• ErrorCode values, GATEWAY_PROTOCOL_VERSION, and GATEWAY_MIN_PROTOCOL_VERSION

Unknown frame types are preserved as raw payloads for forward compatibility.

Versioning and compatibility

• PROTOCOL_VERSION is located in packages/gateway-protocol/src/version.ts, with 4 as its current value.
• The server receives minProtocol and maxProtocol from clients; any range that excludes its present protocol is rejected.
• Unknown frame types are preserved by the Swift models so that older clients remain unaffected.

Schema patterns and conventions

• Strict payloads are handled through additionalProperties: false in most objects.
• For IDs and method/event names, NonEmptyString (Type.String({ minLength: 1 })) serves as the default.
• A discriminator on type is applied to the top-level GatewayFrame.
• When side effects are involved, methods typically demand an idempotencyKey in their params, as seen in send, poll, agent, and chat.send.
• Optional internalEvents can be supplied to agent for orchestration context generated at runtime, such as subagent or cron task completion handoff; consider this internal API surface.

Live schema JSON

The generated JSON Schema is a build artifact and is not stored in the repository. During the package rollout, the current beta schema can be accessed at:

• protocol.schema.json

When you change schemas

1. Within the owning packages/gateway-protocol/src/schema/*.ts module, modify the TypeBox schemas and add them to the nearest protocol-schema-fragment-*.ts file, keeping existing keys in their current order.
2. Register the method or event in src/gateway/server-methods-list.ts.
3. If the new RPC requires operator or node scope classification, update src/gateway/method-scopes.ts accordingly.
4. Execute pnpm protocol:check.
5. Commit the regenerated Swift models.

Related

• Rich output protocol
• RPC adapters